To investigate the effects of fetal intrauterine chromic hypoxia on vascular endothelial function and nitric oxide synthase expression in the aged rats' offspring.Methods
Pregnant Sprague-Dawley rats were subjected to hypoxia for 3 hours in low pressure cabin with an oxygen concentration of (10±1) % from day 7 to day 21 of pregnancy. At the age of 16 months, endothelium-dependent relaxation was evaluated using isolated rat thoracic aorta rings, and the expression of inducible nitric oxide synthase (iNOS) and endothelial nitric oxide synthase (eNOS) in the aorta was determined by RT-PCR and Western blotting.Results
Endothelium-dependent relaxation of the aorta was significantly decreased in the intrauterine hypoxia group compared to the control group (45.1±14.4% vs 82.7±10.6%, P<0.01). The expression of iNOS was up-regulated and that of eNOS was down-regulated at both mRNA and protein levels in the intrauterine hypoxia group.Conclusion
Intrauterine chronic hypoxia impairs vascular endothelium function in the aged rats' offspring. This effect may be mediated by fetal programming of abnormal iNOS and eNOS expression in the blood vessels.